A garden intelligent irrigation control system

Abstract

The present application relates to the technical field of irrigation control, and discloses a kind of garden intelligent irrigation control system, comprising: data acquisition module, reference side pipe flow and valve area average application intensity are obtained by calculation;Infiltration centroid displacement calculation module, infiltration centroid displacement module length and direction are determined;First moment calculation module, first moment is determined;Target side pipe flow calculation module, target side pipe flow is obtained by solving;Execution amount calculation module, valve area supply pressure set value is determined;Duration balancing module, irrigation duration is determined.The present application quantifies the superimposed influence of wind-induced drift and slope runoff, converts the infiltration centroid shift into executable target side pipe flow, valve opening and valve area supply pressure set value, effectively offsets the imbalance of insufficient water supply on the windward uphill side and excessive water supply on the leeward downhill side, and evenly distributes water in the crop root zone;Under the premise of keeping total water consumption unchanged, duration balancing is completed, which avoids water resource waste and guarantees crop water supply.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of irrigation control, more particularly, it relates to a garden intelligent irrigation control system. BACKGROUND

[0002] The fixed sprinkler system is generally used in the garden scene such as urban park and residential green land. In actual operation, the near-ground wind speed and wind direction directly affect the trajectory of water droplets in the air, and the parameters such as the center height of the sprinkler, the nozzle angle and the front pressure further determine the flight time of the water droplets. The prolonged flight process not only increases the evaporation loss, but also causes the water droplets to drift obviously horizontally to the downwind direction. At the same time, factors such as air temperature and relative humidity can amplify the water volume loss, so that the effective water amount reaching the ground is reduced compared with the designed spraying amount, and the spatial distribution deviates from the initial design pattern.

[0003] The garden terrain often has continuous or local slope, and the soil has limited infiltration capacity under certain water content and compaction conditions. When the average application intensity of the valve area exceeds the soil infiltration capacity, a thin layer of surface flow will be formed on the ground and will move along the maximum downhill direction. The water droplet drift caused by atmospheric factors and the water movement caused by slope runoff are superimposed on each other, so that the water amount that really enters the soil presents the distribution characteristics of enrichment on the downwind and downhill side and sparseness on the upwind and uphill side. The geometric center of the infiltration water amount is offset to the downwind and downhill direction, and the target root zone dry and wet patches continue to exist.

[0004] The current garden sprinkler control mostly adopts the mode of partitioning, constant pressure and constant time, or only adjusts the total irrigation time according to the reference evaporation and empirical coefficient. This kind of mode only pays attention to the total water amount matching and the nominal spraying uniformity of the sprinkler, and does not take the real-time relationship between the wind direction and the slope direction, the wind-induced displacement and the influence of the surface runoff on the spatial distribution of the infiltration water amount into the quantitative calculation. There is also no clear method to convert the infiltration center offset into specific executable parameters. Therefore, it is impossible to offset the offset by adjusting the branch flow, the valve opening and the valve area pressure supply, which leads to long-term off-target water supply of the target root zone, causing waste of water resources and increasing the maintenance pressure of the green land. SUMMARY

[0005] The present application provides a garden intelligent irrigation control system, which solves the technical problems in the background art.

[0006] The present application provides a garden intelligent irrigation control system, which includes:

[0007] The data acquisition module obtains the maximum downhill direction and slope, obtains the near-ground wind speed and wind direction, and calculates the wind-slope angle and the direction unit vector accordingly. The reference side pipe flow and the average application intensity of the valve area are calculated in combination with the sprinkler pipe network parameters.

[0008] The sprinkler pipe network parameters include: sprinkler center height, nozzle elevation angle, nozzle front pressure, nozzle cross-sectional area, nozzle flow coefficient, valve area, irrigation time length, and projection coordinates of the lateral pipe on the direction unit vector;

[0009] The infiltration centroid displacement calculation module calculates the wind-induced drift length according to the near-ground wind speed and the sprinkler pipe network parameters, calculates the runoff translation length according to the average application intensity of the valve area, the slope, and the sprinkler pipe network parameters, and determines the infiltration centroid displacement module length and direction in combination with the wind-slope angle;

[0010] The first moment calculation module determines the effective volume according to the average wind drift and the evaporation loss ratio, and the reference lateral pipe flow and the irrigation time length, and determines the first moment according to the effective volume and the infiltration centroid displacement module length.

[0011] The target lateral pipe flow calculation module, under the premise of keeping the total flow unchanged, solves the target lateral pipe flow by taking the first moment and the irrigation time length as constraints and taking the projection coordinates of the lateral pipe on the direction unit vector as independent variables.

[0012] The execution amount calculation module determines the valve opening degree according to the target lateral pipe flow and the valve parameter, determines the head loss along each branch according to the branch length, the branch pipe diameter, and the Hazen-Williams coefficient, and determines the valve area pressure setting value according to the maximum value of the sum of the expected pressure difference and the head loss along each branch.

[0013] The time length balancing module, under the premise of keeping the total water consumption unchanged, determines the irrigation time length according to the effective volume, the average wind drift, the evaporation loss ratio, and the target lateral pipe flow.

[0014] Further, the maximum downhill direction unit vector and the slope are calculated by obtaining the digital elevation model, the near-ground wind speed and the wind direction are obtained by the sensor, and the wind direction is converted into the wind direction unit vector; the wind-slope angle is calculated according to the inner product of the wind direction unit vector and the maximum downhill direction unit vector.

[0015] The product of the near-ground wind speed and the wind direction unit vector, the product of the fixed weight and the maximum downhill direction unit vector are superimposed, and the superimposed vector is normalized to obtain the direction unit vector.

[0016] The reference lateral pipe flow of each lateral pipe is calculated according to the nozzle flow coefficient, the nozzle cross-sectional area, the nozzle front pressure, and the water density.

[0017] The sum of the reference lateral pipe flows of all lateral pipes is calculated, and the average application intensity of the valve area is obtained by calculating the ratio of the sum to the valve area.

[0018] Further, the flight time of the drop spectrum is calculated according to the sprinkler center height, the gravitational acceleration, and the nozzle elevation angle; and the wind-induced drift length is obtained by multiplying the near-ground wind speed and the flight time.

[0019] The difference between the average application intensity of the valve area and the equivalent infiltration capacity is calculated, and the difference is non-negative processed and converted into excess flux velocity; the excess flux velocity is multiplied by the interval between adjacent branch pipes or spray belts to obtain the unit width flow.

[0020] Further, the tangent value of the slope is calculated to obtain a slope conversion quantity; according to the Manning roughness coefficient, the unit width flow and the slope conversion quantity, the Manning formula and the continuity equation are solved to calculate the water film thickness and the thin layer flow velocity; the thin layer flow velocity is multiplied by the initial irrigation time to obtain the runoff translation length;

[0021] According to the wind-induced drift length, the runoff translation length and the wind slope angle, the modulus of the infiltration centroid displacement is calculated by vector synthesis; the direction of the infiltration centroid displacement is determined by combining the direction unit vector and the modulus of the infiltration centroid displacement.

[0022] Further, the sum of the reference side pipe flow of all side pipes is calculated; the loss correction coefficient is obtained by subtracting the average wind drift and evaporation loss ratio from the numerical value;

[0023] The loss correction coefficient, the sum of the reference side pipe flow and the initial irrigation time are sequentially multiplied to obtain the effective volume; the effective volume is multiplied by the modulus of the infiltration centroid displacement to obtain the first moment.

[0024] Further, the flow increment of each side pipe is set, and the constraint condition that the sum of all flow increments is zero is determined; the condition that the sum of the product of all flow increments and the corresponding side pipe projection coordinates satisfies the first moment constraint is determined.

[0025] Further, the sum of all side pipe projection coordinates is calculated, and the sum is divided by the number of side pipes to obtain the average projection coordinate;

[0026] The difference between the projection coordinate of each side pipe and the average projection coordinate is calculated, and the sum of the squares of all differences is calculated to obtain the projection coordinate dispersion measure;

[0027] According to the first moment, the initial irrigation time, the projection coordinate dispersion measure and the difference between the projection coordinate of each side pipe and the average projection coordinate, the flow increment of each side pipe is calculated;

[0028] The reference side pipe flow of each side pipe is added to the corresponding flow increment to obtain the target side pipe flow of each side pipe.

[0029] Further, the target side pipe flow and the valve parameters of each branch are obtained, and the valve parameters include: the valve flux coefficient, the valve flow characteristic index and the valve expected pressure difference;

[0030] The square root of the pressure difference of the valve at two ends is calculated in combination with the water density, the target side pipe flow is divided by the product of the valve flux coefficient and the square root, and the calculation result is subjected to the square root operation corresponding to the valve inherent flow characteristic index to obtain the valve opening degree of each branch.

[0031] Further, the length, pipe diameter and Hazen-Williams coefficient of each branch are obtained, the head loss along the pipeline of each branch is calculated according to the branch length, pipe diameter, Hazen-Williams coefficient and target side pipe flow through the pipeline head loss calculation formula;

[0032] The water density, gravitational acceleration and head loss along the pipeline are subjected to product operation in sequence, and the head loss along the pipeline of each branch is converted into the pressure loss along the pipeline;

[0033] The sum of the pressure loss along the pipeline of each branch and the expected pressure difference of the corresponding branch valve is calculated, and the maximum value of the sum in the branch is selected as the valve area pressure setting value.

[0034] Further, the sum of the target side pipe flow of all side pipes is calculated, and the loss correction coefficient is obtained by subtracting the average wind drift and evaporation loss ratio from the numerical value;

[0035] The loss correction coefficient is subjected to product operation with the sum of the target side pipe flow to obtain the effective flow sum, and the irrigation time after balancing is obtained by dividing the effective volume by the effective flow sum.

[0036] The beneficial effects of the present application are that: the present application quantifies the superimposed influence of wind-induced drift and slope runoff, converts the infiltration center offset into executable target side pipe flow, valve opening degree and valve area pressure setting value, effectively offsets the imbalance state of insufficient water supply on the upwind and uphill side and excessive water supply on the downwind and downhill side, and uniformly distributes water in the crop root zone; at the same time, the time balancing is completed under the premise of keeping the total water consumption unchanged, fully considering the wind drift and evaporation loss, avoiding water resource waste and ensuring crop water supply; thereby reducing the implementation and operation cost, realizing the unity of irrigation uniformity, water resource utilization rate and system stability, and adapting to various garden topography and meteorological conditions. BRIEF DESCRIPTION OF DRAWINGS

[0037] Fig. 1 is a flow chart of a garden intelligent irrigation control system of the present application;

[0038] Fig. 2 is a flow chart of a garden intelligent irrigation control method of the present application.

[0039] In the figure: data acquisition module 101, infiltration center displacement calculation module 102, first moment calculation module 103, target side pipe flow calculation module 104, execution amount calculation module 105, time balancing module 106. DETAILED DESCRIPTION

[0040] The subject matter described herein will now be discussed with reference to example implementations. It should be understood that the implementations discussed are merely for illustration and that the elements of the discussions can be modified, supplemented, or omitted in different examples. Additionally, features described in relation to some examples can also be combined in other examples.

[0041] It should be noted that the technical terms or scientific terms used in one or more embodiments of the present application should be understood as the general meaning understood by a person having ordinary skills in the art to which the present application pertains, unless otherwise defined. The terms "first", "second", and similar words used in one or more embodiments of the present application do not represent any order, number, or importance, but are only used to distinguish different components. The terms "include" or "contain" and similar words mean that the elements or objects appearing before the words encompass the elements or objects listed after the words and their equivalents, and do not exclude other elements or objects. The terms "connected" or "linked" and similar words do not mean only physical or mechanical connections, but can include electrical connections, whether direct or indirect. The terms "upper", "lower", "left", "right", and the like are used only to indicate relative positional relationships, and when the absolute positions of the described objects are changed, the relative positional relationships can also be changed accordingly.

[0042] As shown in Figs. 1-2 A garden intelligent irrigation control system, comprising:

[0043] A data acquisition module 101 is configured to obtain the maximum downhill direction and slope, obtain the near-ground wind speed and wind direction, calculate the wind-slope angle and the direction unit vector, and calculate the reference lateral pipe flow and the average application intensity in the valve area in combination with the sprinkler pipe network parameters;

[0044] The sprinkler pipe network parameters include the sprinkler head center height, the nozzle elevation angle, the nozzle front pressure, the nozzle cross-sectional area, the nozzle flow coefficient, the valve area, the irrigation duration, and the projection coordinates of the lateral pipe on the direction unit vector;

[0045] An infiltration centroid displacement calculation module 102 is configured to calculate the wind-induced drift length according to the near-ground wind speed and the sprinkler pipe network parameters, calculate the runoff translation length according to the average application intensity in the valve area, the slope, and the sprinkler pipe network parameters, and determine the infiltration centroid displacement module length and direction in combination with the wind-slope angle;

[0046] A first moment calculation module 103 is configured to determine the effective volume according to the average wind drift and the evaporation loss ratio, the reference lateral pipe flow, and the irrigation duration, and determine the first moment according to the effective volume and the infiltration centroid displacement module length;

[0047] a target side pipe flow calculation module 104 configured to solve for the target side pipe flow by taking the first moment and irrigation time as constraints and taking the projection of the side pipe on the direction unit vector as the independent variable while keeping the total flow constant;

[0048] an execution amount calculation module 105 configured to determine the valve opening according to the target side pipe flow and the valve parameters, determine the head loss of each branch according to the branch length, branch diameter and Hazen-Williams coefficient, and determine the valve area pressure setting value according to the maximum value of the sum of the expected pressure difference of each branch and the head loss;

[0049] a time length balancing module 106 configured to determine the irrigation time according to the effective volume, average wind drift, evaporation loss ratio and target side pipe flow while keeping the total water consumption constant.

[0050] In an embodiment of the present application, the maximum downhill direction unit vector and the slope are calculated by obtaining a digital elevation model, the near-ground wind speed and the wind direction are obtained by a sensor, and the wind direction is converted into a wind direction unit vector; the wind-slope angle is calculated according to the inner product of the wind direction unit vector and the maximum downhill direction unit vector.

[0051] The product of the near-ground wind speed and the wind direction unit vector and the product of the fixed weight and the maximum downhill direction unit vector are superimposed, and the superimposed vector is normalized to obtain the direction unit vector.

[0052] The reference side pipe flow of each side pipe is calculated according to the nozzle flow coefficient, nozzle cross-sectional area, nozzle front pressure and water density.

[0053] The sum of the reference side pipe flows of all side pipes is calculated, and the ratio of the sum to the valve area is calculated to obtain the valve area average application intensity.

[0054] It should be noted that the digital elevation model is a rasterized ground elevation dataset used to extract the slope and slope direction information of the ground; the maximum downhill direction unit vector represents the downhill direction of the steepest part of the ground with a modulus of 1; the slope represents the inclination of a point on the ground, i.e. the tangent value of the angle between the horizontal plane and the ground tangent; the near-ground wind speed represents the air flow speed at the installation height of the ground nozzle, which is collected by a wind speed sensor in the field; the wind direction represents the direction of air flow, which is collected by a wind direction sensor; the wind direction unit vector represents the conversion of the collected wind direction into a vector pointing to the direction of the wind and having a modulus of 1, for example, converting the collected wind direction into a horizontal pointing vector based on the geographic coordinate system, and then dividing the vector by its own modulus; the wind-slope angle represents the angle between the wind direction and the maximum downhill direction, i.e. first calculating the inner product of the wind direction unit vector and the maximum downhill direction unit vector (multiplying the corresponding components of the two vectors and summing them), and then calculating the arccosine value of the inner product, and the result is the wind-slope angle.

[0055] Specifically, taking the center point of the irrigation area as the origin, the north-south direction as the y-axis (north as the positive direction of the y-axis), the east-west direction as the x-axis (east as the positive direction of the x-axis), the azimuth angle as 0 degrees with north as the positive direction, and clockwise rotation as the positive direction, the range is 0 to 360 degrees. First, convert the measured wind direction to the direction angle (the difference between the wind direction and the direction angle is 180 degrees), then calculate the x-axis and y-axis components according to the direction angle, and finally normalize the components to obtain the unit vector. If the measured wind direction is east, the direction is west, corresponding to a direction angle of 270 degrees, when calculating the components, convert 270° to radian (270° x π / 180° = 3π / 2), the x-axis component = sin(3π / 2) = -1, the y-axis component = cos(3π / 2) = 0, and finally the unit vector (-1, 0) is obtained.

[0056] It should be noted that the fixed weight represents the coefficient for balancing the influence of the near-surface wind speed and the maximum downhill direction in the direction synthesis process, and the value is fixed at 1, without the need for additional calibration; the direction unit vector represents a standardized vector with a modulus of 1 after integrating the wind and slope direction influences; the nozzle flow coefficient represents a dimensionless coefficient determined by the nozzle structure, reflecting the flow efficiency of the nozzle, which is provided by the nozzle manufacturer or obtained through test calibration, i.e., by measuring the actual flow of the nozzle under a known pressure and comparing it with the theoretical flow under the same pressure, the ratio of the two is the nozzle flow coefficient; the nozzle cross-sectional area represents the cross-sectional area at the nozzle outlet, which is calculated from the nozzle diameter; the nozzle pre-pressure represents the fluid pressure at the nozzle inlet in the irrigation system, which can be collected by a system pressure sensor or set; the reference side pipe flow represents the initial outflow flow of each side pipe without regulation, which is calculated from the nozzle-related parameters and water density; the valve area represents the total area of the irrigation area controlled by a single control valve; the average application intensity of the valve area represents the average water supply intensity per unit area of the valve area, which is obtained by the ratio of the sum of all side pipe reference flows to the valve area, and is used to judge whether the water supply exceeds the soil infiltration capacity, with the unit of millimeters per hour.

[0057] Specifically, the direction unit vector is calculated as follows:

[0058] ;

[0059] where U represents the near-surface wind speed, represents the wind direction unit vector, represents the fixed weight, represents the maximum downhill direction unit vector.

[0060] Specifically, the calculation formula of the reference side pipe flow of the jth side pipe is as follows:

[0061] ;

[0062] wherein represents a nozzle flow coefficient, represents a nozzle cross-sectional area, represents a nozzle front pressure, represents a water density.

[0063] In one embodiment of the present application, the flight time of the drop spectrum is calculated according to the sprinkler center height, the gravity acceleration and the nozzle elevation angle; the wind-induced drift length is obtained by multiplying the near-ground wind speed and the flight time;

[0064] The difference between the average application intensity of the valve area and the equivalent infiltration capacity is calculated, and the difference is non-negative processed and converted into the excess flux speed; the unit width flow is obtained by multiplying the excess flux speed and the adjacent branch pipe or the spray band spacing.

[0065] It should be noted that the nozzle elevation angle represents the included angle between the nozzle axis and the horizontal line, which is determined by the nozzle installation angle or the manufacturer's calibration; the flight time of the drop spectrum represents the average time of the sprayed water droplets from the nozzle to the ground, and the calculation formula is twice the sprinkler center height divided by the gravity acceleration, and the square root of the result is divided by the cosine value of the nozzle elevation angle; the wind-induced drift length represents the horizontal distance of the water droplets carried by the wind during the flight, and the wind-induced drift length is obtained by multiplying the near-ground wind speed and the flight time of the drop spectrum; the equivalent infiltration capacity considers the influence of the slope angle, and the maximum rate of water absorption per unit time of the soil; the excess flux speed represents the part of the average application intensity of the valve area exceeding the equivalent infiltration capacity, which is converted into a parameter with a speed dimension, and the unit is meters per second, and the calculation formula is to calculate the difference between the average application intensity of the valve area and the equivalent infiltration capacity, and if the difference is negative, it is taken as zero, and then the result is divided by 3600 and 1000 in turn; the adjacent branch pipe or the spray band spacing represents the horizontal distance between two adjacent branch pipes or spray bands in the irrigation system; the unit width flow represents the water flow per unit length in the width direction of the slope.

[0066] In one embodiment of the present application, the tangent value of the slope is calculated to obtain the slope conversion quantity; the water film thickness and the thin layer surface flow speed are calculated by simultaneously solving the Manning formula and the continuity equation according to the Manning roughness coefficient, the unit width flow and the slope conversion quantity; the runoff translation length is obtained by multiplying the thin layer surface flow speed and the initial irrigation time;

[0067] The infiltration centroid displacement module length is calculated by vector synthesis according to the wind-induced drift length, the runoff translation length and the wind-slope included angle; the direction of the infiltration centroid displacement is determined in combination with the direction unit vector and the infiltration centroid displacement module length.

[0068] It should be noted that the slope conversion amount is to convert the slope angle into a dimensionless parameter, that is, the tangent value of the slope; the Manning roughness coefficient is a dimensionless parameter representing the roughness of the ground surface, which affects the slope water flow velocity, and is valued according to the type of ground cover, for example, the value corresponding to grassland is 0.03 to 0.05, the value corresponding to bare soil is 0.02 to 0.03, and the value corresponding to hardened ground is 0.01 to 0.02; the Manning formula is an empirical formula describing the relationship between the velocity of open channel flow and the roughness, water depth, and slope, which is used to calculate the thin layer flow velocity on the slope, and the calculation formula is that the thin layer flow velocity is equal to the reciprocal of the Manning roughness coefficient, multiplied by the square of two-thirds of the water film thickness, and then multiplied by the square root of one-half of the slope conversion amount; the continuity equation is an equation representing the conservation of water flow mass, which is used to solve the water film thickness and the thin layer flow velocity simultaneously, and the calculation formula is that the unit width flow is equal to the thin layer flow velocity multiplied by the water film thickness.

[0069] It should be noted that the water film thickness is the average thickness of the thin layer runoff on the slope, and the calculation formula is to multiply the Manning roughness coefficient by the unit width flow, and then divide by the square root of the slope conversion amount, and then take the cube of five-thirds of the result; the thin layer flow velocity is the average flow velocity of the thin layer runoff on the slope, and the calculation formula is to take the square of two-fifths of the unit width flow, multiply by the cube of three-tenths of the slope conversion amount, and then divide by the cube of three-fifths of the Manning roughness coefficient; the initial irrigation time length represents the preset irrigation time before the distribution is balanced; the runoff translation length represents the horizontal distance migrated by the thin layer water flow on the slope within the initial irrigation time length, and the calculation formula is to multiply the thin layer flow velocity by the initial irrigation time length; the infiltration mass center displacement module length is the straight line distance of the offset of the infiltration mass center relative to the spraying geometric center, and the calculation formula is to add the square of the wind-induced drift length to the square of the runoff translation length, and then add twice the product of the wind-induced drift length and the runoff translation length, and then multiply by the cosine value of the wind slope angle, and then take the square root of the sum; the direction of the infiltration mass center displacement is the spatial pointing of the offset of the infiltration mass center, and the displacement vector is combined with the direction unit vector, and the direction of the displacement vector is consistent with the direction unit vector.

[0070] Specifically, the calculation formula of the water film thickness h is as follows:

[0071] ;

[0072] Specifically, the calculation formula of the thin layer flow velocity is as follows:

[0073] ;

[0074] wherein n represents the Manning roughness coefficient, Q represents the unit width flow, and S represents the slope conversion amount.

[0075] Specifically, the calculation formula of the infiltration mass center displacement module length is as follows:

[0076] ;

[0077] wherein represents the wind-induced drift length, represents the runoff translation length, represents the wind slope angle.

[0078] In an embodiment of the present application, the sum of the reference lateral pipe flow of all lateral pipes is calculated; the loss correction coefficient is obtained by subtracting the average wind drift and evaporation loss ratio from the numerical value one;

[0079] The loss correction coefficient, the sum of the reference lateral pipe flow and the initial irrigation time length are sequentially multiplied to obtain the effective volume; the effective volume is multiplied by the inositol centroid displacement module length to obtain the first moment.

[0080] It should be noted that the sum of the reference lateral pipe flow is the total flow obtained by adding the reference lateral pipe flow of all independently adjustable lateral pipes in the valve area, which is used to quantify the total water supply capacity of the system when not controlled; the average wind drift and evaporation loss ratio represents the proportion of the loss caused by the drift of water droplets and the evaporation of water in the spraying process due to wind, which is dimensionless, used to correct the actual effective water supply volume, which can be determined by experiment (under the same wind speed, temperature and humidity conditions, the actual landing water volume is compared with the total sprayed water volume to obtain) or using industry experience value (0.05 to 0.1 in windless environment, 0.1 to 0.25 in windy environment); the loss correction coefficient is the proportion of the water volume actually participating in the surface infiltration after deducting the wind drift and evaporation loss, which is dimensionless, used to convert the theoretical water supply volume into the effective volume. The effective volume is the total volume of water that actually reaches the ground and can participate in infiltration after deducting the wind drift and evaporation loss, and the calculation formula is to multiply the loss correction coefficient by the sum of the reference lateral pipe flow, and then multiply the result by the initial irrigation time length, to sequentially complete two multiplication operations to obtain the effective volume. The first moment is the product of the volume and distance required to offset the inositol centroid shift.

[0081] Specifically, the calculation formula of the effective volume is as follows:

[0082] ;

[0083] wherein N represents the number of independently adjustable lateral pipes, represents the average wind drift and evaporation loss ratio, represents the reference lateral pipe flow of the jth lateral pipe, and T represents the initial irrigation time length.

[0084] In an embodiment of the present application, the flow increment of each lateral pipe is set, and the constraint condition that the sum of all flow increments is zero is specified; the condition that the sum of the products of all flow increments and the corresponding lateral pipe projection coordinates satisfies the first moment constraint is specified.

[0085] It should be noted that the flow increment is the adjustment amount of the reference lateral pipe flow of each lateral pipe, the unit is cubic meters per second, which is used to correct the original flow to offset the infiltration centroid deviation, which can be positive or negative (positive value increases the flow, negative value reduces the flow), the calculation formula is to divide the negative first moment by the initial irrigation time, then divide by the projection coordinate dispersion measure, and finally multiply the difference between the projection coordinate of the lateral pipe and the average value of the projection coordinate, the result is the flow increment of the lateral pipe. The first moment constraint is a constraint rule for ensuring that the flow adjustment can offset the infiltration centroid deviation, the core is to realize the first moment offset through the correlation between the flow increment and the lateral pipe position; specifically, the sum of the products of the flow increments of all lateral pipes and the corresponding projection coordinates of the lateral pipes is equal to the ratio of the negative first moment to the initial irrigation time.

[0086] It should be noted that the sum of all flow increments is set to zero, the purpose is to keep the total water supply flow of the system unchanged before and after regulation, this constraint can adapt to the operation conditions of the irrigation system, avoid the total water consumption exceeding the crop water allocation quota or the rated carrying capacity of the water supply equipment due to flow adjustment, without additional adjustment of core water supply facilities such as water pump and pipe network, to ensure stable operation of the system, while avoiding waste of water resources or insufficient water for crops. The sum of the products of all flow increments and the corresponding projection coordinates of the lateral pipes satisfies the first moment constraint, the purpose is to generate a reverse first moment through flow distribution, which exactly offsets the original deviation of the infiltration centroid, this constraint ensures that the flow adjustment can accurately act on the direction of the infiltration centroid deviation, so that the infiltration centroid returns to the spraying geometric center, makes the water evenly distributed in the crop root zone, avoids local waterlogging or drought, and improves the irrigation effect and water use efficiency. Under the synergistic action of the two constraint conditions, the stability and economy of the system operation are ensured, and the regulation and control target of uniform irrigation is realized.

[0087] Specifically, the flow increment of the jth lateral pipe The calculation formula is as follows:

[0088] ;

[0089] Wherein represents the first moment, T represents the initial irrigation time, represents the projection coordinate dispersion measure, represents the projection coordinate of the jth lateral pipe in the direction unit vector, represents the average value of the projection coordinate.

[0090] In an embodiment of the present application, the sum of the projection coordinates of all lateral pipes is calculated, and the sum is divided by the number of lateral pipes to obtain the average value of the projection coordinate;

[0091] The difference between the projection coordinate of each side pipe and the average value of the projection coordinates is calculated, and the squares of all the differences are summed to obtain a projection coordinate dispersion measure;

[0092] The flow increment of each side pipe is calculated according to the first moment, the initial irrigation time length, the projection coordinate dispersion measure and the difference between the projection coordinate of each side pipe and the average value of the projection coordinates;

[0093] The reference side pipe flow of each side pipe is added to the corresponding flow increment to obtain the target side pipe flow of each side pipe.

[0094] It should be noted that the total projection coordinate is the sum of the projection coordinates of all independently adjustable side pipes, and the unit is meter. The total projection coordinate is obtained by accumulating the projection coordinates of each side pipe one by one. The difference between the projection coordinate and the average value of the projection coordinates is the result of subtracting the average value of the projection coordinates of all side pipes from the projection coordinate of a single side pipe, which is used to quantify the position deviation of a single side pipe relative to the geometric center of the side pipe group. The side pipe projection coordinate is a one-dimensional coordinate of each side pipe in the direction unit vector, and the unit is meter, which is used to represent the position distribution of the side pipe in the flow distribution direction. The projection coordinate dispersion measure represents the numerical value of the distribution dispersion degree of all side pipes in the flow distribution direction. The target side pipe flow is the final flow that each side pipe needs to output after the flow increment adjustment, and the unit is cubic meters per second.

[0095] In an embodiment of the present application, the target side pipe flow and valve parameters of each branch are obtained, and the valve parameters include: valve flux coefficient, valve flow characteristic index and valve expected pressure difference;

[0096] The square root of the pressure difference between the two ends of the valve is calculated in combination with the water density, the target side pipe flow is divided by the product of the valve flux coefficient and the square root, and then the calculation result is subjected to the square root operation corresponding to the valve inherent flow characteristic index to obtain the valve opening degree of each branch.

[0097] It should be noted that the valve flux coefficient is a parameter representing the through-flow capacity of the valve, reflecting the conduction efficiency of the valve structure to water flow, and is provided by the valve manufacturer or obtained by test calibration. The valve flow characteristic index is a dimensionless parameter representing the relationship between the valve flow and the opening degree, which is determined by the valve type, for example, 1 to 1.5 for an equal percentage valve, 2 for a parabolic valve, and 0.5 to 0.8 for a quick-opening valve. The valve flow characteristic index is the pressure difference required to be maintained between the two ends of the valve during normal operation, which is set according to the working pressure requirement of the nozzle. The calculation formula of the square root of the pressure difference between the two ends of the valve is the square root of the result of dividing the valve expected pressure difference by the water density. The valve opening degree is the opening degree of the valve, which is dimensionless and has a value range of 0 to 1, and is used to control the actual flow of the branch. The calculation formula is to divide the target side pipe flow by the product of the valve flux coefficient and the square root of the pressure difference between the two ends of the valve, and then to perform the square root operation on the obtained result. The square root operation is performed for the inverse of the valve flow characteristic index.

[0098] It should be noted that if the manufacturer does not provide the valve flux coefficient, it can be calibrated by itself, and the calibration method is to measure the actual flow of the valve under a known pressure difference, and divide the actual flow by the product of the square root of the pressure difference and the square root of the valve flow characteristic index. If the manufacturer does not provide the valve flow characteristic index, it is determined according to the above valve type. The expected pressure difference of the valve is determined according to the minimum pressure required for the nozzle to work normally, combined with the overall hydraulic design of the pipe network, to ensure that the nozzle can stably flow and the spraying effect meets the standard, and is usually set to 50,000 to 100,000 pascals. It can be fine-tuned according to the actual nozzle model and irrigation scene.

[0099] Specifically, the valve opening degree of the jth branch The calculation formula is as follows:

[0100] ;

[0101] Wherein represents the target side pipe flow of the jth branch, represents the valve flux coefficient of the jth branch, represents the expected pressure difference of the valve of the jth branch, represents the water density, m represents the valve flow characteristic index.

[0102] In an embodiment of the present application, the length, pipe diameter and Hazen-Williams coefficient of each branch are obtained, and the head loss along the pipeline is calculated according to the length, pipe diameter, Hazen-Williams coefficient and target side pipe flow of each branch.

[0103] The water density, gravitational acceleration and head loss along the pipeline are sequentially multiplied, and the head loss along the pipeline of each branch is converted into pressure loss along the pipeline.

[0104] The sum of the pressure loss along the pipeline of each branch and the corresponding branch valve expected pressure difference is calculated; the maximum value of the sum in the branch is selected as the valve area pressure setting value.

[0105] It should be noted that the branch length is the total length of the pipeline from the control valve to the terminal nozzle of a single branch, which affects the energy loss of water flow along the pipeline; the branch pipe diameter is the inner diameter of the pipeline of a single branch; the Hazen-Williams coefficient is a dimensionless parameter representing the roughness of the inner wall of the pipeline. The larger the value, the smaller the pipeline resistance, which is determined according to the pipeline material (polyvinyl chloride pipe 140-150, steel pipe 100-120, cast iron pipe 80-100); the pipeline head loss calculation formula is an empirical formula for calculating the energy loss of water flow in the pipeline. The Hazen-Williams formula is used in the present application. The formula form is that the head loss along the pipeline is equal to 10.67 times the length of the branch, and then multiplied by the 1.852 power of the target side pipe flow, and the result is divided by the product of the 1.852 power of the Hazen-Williams coefficient and the 4.87 power of the branch pipe diameter.

[0106] Specifically, the head loss along the j-th branch. The calculation formula is as follows:

[0107] ;

[0108] in This represents the length of the pipe in the j-th branch. Indicates the target side pipe flow rate of the j-th branch. This represents the Hadzen-Williams coefficient. This represents the pipe diameter of the j-th branch.

[0109] It should be noted that head loss is the energy loss caused by friction when water flows in a pipe, and it is calculated directly using the pipe friction loss calculation formula (Hazen-Williams formula). Pressure loss is the pressure loss corresponding to the head loss, measured in Pascals, representing the resistance of the pipe to the water flow. It is calculated by multiplying the water density by the acceleration due to gravity, then multiplying by the head loss, and so on. The sum of branch pressure loss and expected pressure difference is the total pressure required for normal operation of a single branch, including pipe resistance loss and valve operating pressure difference. It is calculated by adding the pressure loss of a single branch to the corresponding valve's expected pressure difference. The valve zone supply pressure setpoint is the minimum water supply pressure that the system must provide to ensure that all branches meet flow requirements.

[0110] It should be noted that the target side pipe flow rate is converted into valve opening and valve zone pressure setting values ​​that the system can directly execute. By accurately calculating the valve opening, it is ensured that each branch can output the target flow rate. By calculating the pipeline friction loss and taking the maximum pressure demand, the pressure setting value is determined to ensure that all branches can overcome pipeline resistance and meet the valve working pressure difference. This not only adapts to the inherent characteristics of valves and pipelines, but also avoids insufficient flow or excessive pressure in some branches, ensuring the stable operation of the irrigation system and achieving the control goal of uniform water distribution.

[0111] In one embodiment of the present invention, the sum of the target side pipe flow rates of all side pipes is calculated; the loss correction coefficient is obtained by subtracting the ratio of average wind drift to evaporation loss from the numerical value.

[0112] The loss correction factor is multiplied by the sum of the target side pipe flow rates to obtain the effective flow rate; the effective volume is divided by the effective flow rate to obtain the balanced irrigation duration.

[0113] It should be noted that the effective flow sum is the total flow actually delivered to the ground surface after deducting the wind drift evaporation loss, the calculation formula is that the sum of the loss correction coefficient and the target side pipe flow is multiplied, and the result is the effective flow sum; the irrigation time after balancing is the irrigation time after flow adjustment, the irrigation time corrected to keep the total water consumption unchanged is the final irrigation time of the system. The flow of each side pipe before is changed to offset the inositol center offset, the total flow may deviate from the initial design, and the time length balancing can avoid excessive or insufficient water consumption, accurately adapt the crop water allocation quota and water resource control demand, ensure the crop water supply, and eliminate water resource waste; the introduction of the loss correction coefficient fully considers the actual influence of wind drift and evaporation, makes the irrigation time after balancing more suitable for field working conditions, avoids the time deviation caused by ignoring the loss, and improves the irrigation accuracy.

[0114] In one embodiment of the present application, as shown in Fig. 2 A garden intelligent irrigation control method, comprising the following steps:

[0115] Step S201, the maximum downhill direction and slope are obtained, the near-ground wind speed and wind direction are obtained, the wind-slope angle and the direction unit vector are calculated, the reference side pipe flow and the average application intensity of the valve area are calculated combined with the sprinkler pipe network parameters;

[0116] Step S202, the wind-induced drift length is calculated according to the near-ground wind speed and the sprinkler pipe network parameters, the runoff translation length is calculated according to the average application intensity of the valve area, the slope and the sprinkler pipe network parameters, and the inositol center displacement module length and direction are determined combined with the wind-slope angle;

[0117] Step S203, the effective volume is determined according to the average wind drift and evaporation loss ratio, the reference side pipe flow and the irrigation time, and the first moment is determined according to the effective volume and the inositol center displacement module length;

[0118] Step S204, under the premise of keeping the total flow unchanged, the target side pipe flow is solved by taking the first moment and the irrigation time as constraints, and taking the projection coordinates of the side pipe on the direction unit vector as independent variables;

[0119] Step S205, the valve opening is determined according to the target side pipe flow and the valve parameter, the head loss along each branch is determined according to the branch length, the branch diameter and the Hazen-Williams coefficient, and the valve area pressure setting value is determined according to the maximum value of the sum of the expected pressure difference and the head loss along each branch;

[0120] Step S206, under the premise of keeping the total water consumption unchanged, the irrigation time is determined according to the effective volume, the average wind drift, the evaporation loss ratio and the target side pipe flow.

[0121] It should be noted that the interval and the threshold size are set for the convenience of comparison, wherein the size of the threshold depends on how much sample data and the base number set by the person skilled in the art for each group of sample data, as long as it does not affect the proportional relationship between the parameters and the quantized values. And the above formula is the calculation of the dimensionless value, the formula is obtained by collecting a large amount of data to simulate the formula of the nearest real situation, and the preset parameters in the formula are set by the person skilled in the art according to the actual situation.

[0122] The above describes the embodiments of the present embodiment, but the present embodiment is not limited to the specific embodiments described above, and the specific embodiments described above are only illustrative but not limiting, and a person skilled in the art can make many forms under the inspiration of the present embodiment, which all belong to the protection of the present embodiment.

Claims

1. A smart irrigation control system for gardens, characterized in that, include: The data acquisition module obtains the maximum downhill direction and slope, and the near-ground wind speed and direction. Based on this, it calculates the wind slope angle and direction unit vector, and combines the sprinkler irrigation network parameters to calculate the baseline side pipe flow rate and the average application intensity of the valve area. The parameters of the sprinkler network include: sprinkler center height, nozzle elevation angle, nozzle inlet pressure, nozzle cross-sectional area, nozzle flow coefficient, valve area, irrigation duration, and the projected coordinates of the side pipe on the unit vector of direction; The infiltration centroid displacement calculation module calculates the wind-induced drift length based on the near-ground wind speed and sprinkler irrigation network parameters, and calculates the runoff translation length based on the average application intensity, slope and sprinkler irrigation network parameters of the valve area. It also determines the infiltration centroid displacement modulus and direction by combining the wind slope angle. The first-order moment calculation module determines the effective volume based on the ratio of average wind drift to evaporation loss, the reference side pipe flow rate and irrigation duration, and determines the first-order moment based on the effective volume and the displacement modulus of the infiltration centroid. The target side pipe flow calculation module, under the premise of keeping the total flow constant, uses the first moment and irrigation duration as constraints, and the projected coordinates of the side pipe on the unit vector of the direction as the independent variable to solve for the target side pipe flow. The execution quantity calculation module determines the valve opening based on the target side pipe flow rate and valve parameters, determines the head loss along each branch based on the branch length, branch pipe diameter and Hadzen-Williams coefficient, and determines the valve area pressure setting value based on the maximum value of the sum of the expected valve pressure difference and the head loss along each branch. The duration balancing module determines the irrigation duration based on effective volume, average wind drift, evaporation loss ratio, and target side pipe flow rate, while keeping the total water consumption constant. The digital elevation model is used to calculate the unit vector of the maximum downslope direction and the slope. Near-ground wind speed and wind direction are obtained through sensors, and the wind direction is converted into a unit vector. The wind slope angle is calculated based on the inner product of the unit vector of wind direction and the unit vector of the maximum downslope direction. The product of near-ground wind speed and wind direction unit vector, and the product of fixed weight and maximum downhill direction unit vector are superimposed, and the superimposed vector is normalized to obtain the direction unit vector. The reference flow rate of each side pipe is calculated based on the nozzle flow coefficient, nozzle cross-sectional area, nozzle inlet pressure, and water density. Calculate the sum of the reference side pipe flow rates for all side pipes, and then calculate the ratio of this sum to the valve area to obtain the average application intensity of the valve area. The flight time of the droplet spectrum is calculated based on the nozzle center height, gravitational acceleration, and nozzle elevation angle; the wind-induced drift length is obtained by multiplying the near-ground wind speed with the flight time. Calculate the difference between the average application intensity and the equivalent infiltration capacity of the valve area, and convert the difference into excess flux velocity after non-negation processing; multiply the excess flux velocity with the spacing between adjacent branches or spray lines to obtain the flow rate per unit width. Calculate the tangent of the slope to obtain the slope conversion value; based on the Manning roughness coefficient, the flow rate per unit width, and the slope conversion value, combine the Manning formula and the continuity equation to calculate the water film thickness and the surface flow velocity; multiply the surface flow velocity by the initial irrigation duration to obtain the runoff translation length. Based on the wind-induced drift length, runoff translation length, and wind slope angle, the displacement modulus of the infiltration centroid is obtained through vector synthesis calculation; the direction of the infiltration centroid displacement is determined by combining the directional unit vector and the displacement modulus of the infiltration centroid. Equivalent infiltration capacity represents the maximum rate at which soil can absorb water per unit time after taking into account the effect of slope angle.

2. The intelligent irrigation control system for gardens according to claim 1, characterized in that, Calculate the sum of the reference side pipe flow rates for all side pipes; subtract the ratio of average wind drift to evaporation loss from the numerical value to obtain the loss correction factor; The effective volume is obtained by multiplying the sum of the loss correction coefficient and the reference side pipe flow rate with the initial irrigation duration. The first moment is obtained by multiplying the effective volume with the displacement modulus of the infiltration centroid.

3. The intelligent irrigation control system for gardens according to claim 1, characterized in that, Define the flow increment for each side pipe and clarify the constraint that the sum of all flow increments is zero; clarify the condition that the sum of the products of all flow increments and the projected coordinates of the corresponding side pipes satisfies the first moment constraint.

4. The intelligent irrigation control system for gardens according to claim 3, characterized in that, Calculate the sum of the projected coordinates of all side tubes, divide the sum by the number of side tubes, and obtain the average value of the projected coordinates. Calculate the difference between the projected coordinates of each side tube and the average projected coordinates, and sum the squares of all the differences to obtain the discrete measure of the projected coordinates. The flow increment of each side pipe is calculated based on the first moment, initial irrigation duration, projection coordinate discrepancy measure, and the difference between the projection coordinates of each side pipe and the average projection coordinate. The target side tube flow rate for each side tube is obtained by adding the baseline side tube flow rate of each side tube to the corresponding flow rate increment.

5. The intelligent irrigation control system for gardens according to claim 1, characterized in that, Obtain the target side pipe flow rate and valve parameters for each branch. Valve parameters include: valve flux coefficient, valve flow characteristic index, and valve expected pressure difference. The square root of the pressure difference across the valve is calculated by combining the water density. The target side pipe flow rate is divided by the product of the valve flow coefficient and the square root. The square root of the calculated result is then used to obtain the valve opening degree of each branch.

6. The intelligent irrigation control system for gardens according to claim 5, characterized in that, Obtain the length, pipe diameter, and Hardy-Williams coefficient of each branch. Based on the branch length, pipe diameter, Hardy-Williams coefficient, and target side pipe flow rate, calculate the head loss of each branch using the pipe friction loss calculation formula. The water density, gravitational acceleration, and head loss along the route are multiplied sequentially to convert the head loss along the route of each branch into pressure loss along the route. Calculate the sum of the friction loss along each branch and the expected pressure difference of the corresponding branch valve; select the maximum value of this sum in the branch as the valve area pressure setting value.

7. The intelligent irrigation control system for gardens according to claim 1, characterized in that, Calculate the sum of the target side pipe flow rates for all side pipes; subtract the ratio of average wind drift to evaporation loss from the numerical value to obtain the loss correction factor; The loss correction factor is multiplied by the sum of the target side pipe flow rates to obtain the effective flow rate; the effective volume is divided by the effective flow rate to obtain the balanced irrigation duration.

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